\documentclass{standalone}
\usepackage{tikz}
\usetikzlibrary{patterns}
\begin{document}
\footnotesize
  \begin{tikzpicture}[>=stealth,scale=0.85]
    \foreach \x in{-1,1} {\draw[thick](-1.2,\x-0.05)rectangle++(2.4,0.1);}
    \foreach \x in{-1,1} {\draw[thick](\x-0.05,-0.95)rectangle++(0.1,1.9);}
    \foreach \x in{1.05,-1.05} 
      { 
        \draw[thin](\x,-1.1)--++(0,-0.5); 
        \draw[thin](-1.25,\x)--++(-0.5,0); 
      }
    \draw[thin,<->](-1.5,-1.05)--(-1.5,1.05)node[midway,sloped,above]{$h$};
    \draw[thin,<->](-1.05,-1.4)--(1.05,-1.4)node[midway,above]{$b$};
    \draw[thin](-0.9595,1.05)--(-0.6595,1.3816)(1.05,-0.95)--(1.4405,-0.5184);
    \draw[thin,<->](-0.75,1.2816)--(1.35,-0.6184)node[midway,sloped,above]{$l_2$};
    \draw[thin](0.9595,1.05)--(0.6595,1.3816)(-1.05,-0.95)--(-1.4405,-0.5184);
    \draw[thin,<->](-1.35,-0.6184)--(0.75,1.2816)node[midway,sloped,above]{$l_1$};
  \end{tikzpicture}
\end{document}